Advanced Technology Airborne Computer
# Advanced Technology Airborne Computer

The Advanced Technology Airborne Computer (ATAC) was a product of Itek (a division of Litton Industries), used on US naval aircraft, and the NASA Galileo $(spacecraft).^{:198–201}$

The ATAC was built using AMD 2901 4-bit processors and had a basic cycle time of 250 $ns.^{:198}$ It could be programmed in HAL/S, and could be microprogrammed to add new instructions. The Galileo project added four instructions.

## Use by Galileo project

The Galileo Attitude and Articulation Control System (AACSE) was controlled by two Itek Advanced Technology Airborne Computers (ATAC), built using radiation-hardened $2901s.^{:201,207}$ The project wrote their own GRACOS (Galileo realtime Attitude Control Operating System).

The Galileo project had radiation-hardened 2901 processors made (by Sandia National Lab) for the $spacecraft.^{:202}$

